1. Field of the Invention
The invention relates to a device for supplying voltage in a computer system, and more particularly to a voltage regulating device for dynamically regulating voltage in a computer system.
2. Description of the Related Art
FIG. 1 is a block circuit diagram showing a device for controlling the operating voltage of a CPU according to the prior art. The operating voltage of the CPU is determined according to the type thereof. Basically, all CPUs can be classified into:
1. Socket 7 series--A socket 7 series CPU itself does not include a device for generating a voltage identification signal. Referring to FIG. 1, an external voltage identification signal setting device 12, such as a jumper switch, is needed to output a voltage identification signal to a voltage converter 14. The voltage converter 14 outputs the operating voltage of the CPU according to the received voltage identification signal. At the same time, a voltage monitor 16 estimates a correct voltage according to the voltage identification signal, and then compares it with the output operating voltage. If the output operating voltage is outside a voltage range located around the correct voltage, a warning signal is emitted for users, so that a computer system can be prevented from damages. Furthermore, the voltage monitor 16 is a hardware monitor. Therefore, users can adjust the jumper switch to determine the operating voltage of the CPU.
2. Slot 1, Slot 2 and Socket 370 series--each type of CPU includes the voltage identification signal setting device 12 having a number of pins for providing a voltage identification signal. Moreover, floating/grounding the pins is determined before completely manufacturing the CPU by providing each pin with a pull-down circuit. Referring to FIG. 1, a voltage identification signal is directly transmitted to the voltage converter 14. The voltage converter 14 outputs the operating voltage of the CPU according to the voltage identification signal. Similarly, the voltage monitor has the same function as described above. As an example, an Intel Klamath CPU has 5 pins VID0-VID4 with logic levels 1, 1, 1, 0, 1, respectively, serving as a voltage identification signal. The voltage converter 14 receives the voltage identification signal, and transmits a voltage of 2.8V to the CPU according to a built-in checklist. Moreover, if the pins VID0-VID4 are set at logic levels 1,0,0,0,0, serving a voltage identification signal, the voltage converter 14 receives the voltage identification signal, and transmits a voltage of 2.0V to the CPU. It is obvious from the above that the operating voltage of the CPU depends on its type.
Accordingly, the operating voltages of Slot 1, Slot 2 and Socket 370 series CPUs cannot be set by users. Under some circumstances, the users, however, would like to change the operating voltages thereof. For example, when users require a CPU to operate at an over-clock, it is desirable to increase the operating voltage of the CPU to enhance the stability of the computer system. Inversely, when users require the CPU to operate at a lower frequency, properly lowering the operating voltage of the CPU not only cannot affect the stability of the computer system, but also reduces power consumption and heat created.
As with all similar computer systems, the way to regulate the operating voltages of CPUs is the same as that for Socket 7 series CPUs. That is, the operating voltage of a CPU is set directly by a jumper switch regardless of a voltage identification signal of the CPU. However, it is inconvenient for users because a computer cover must be removed every time the setting is to be changed. Furthermore, if the operating voltage is erroneously set, for example, the operating voltage should be a suggested voltage value of 2.5, and is unintentionally set to a voltage value of 3.5, the CPU may be damaged permanently.